One of the features of machine vision systems can be the ability to recognize a scene and identify features and objects in the scene. Machine vision systems can be used in portable devices, such as head-mounted devices, on industrial robots, driverless cars, and other devices. Over time, the performance of such systems can degrade. The degradation can be difficult to detect so long as the vision system is still generating a depth image. For example, it is difficult to determine whether the assigned depths are accurate.
Different types of depth camera technology exist. Time-of-flight (TOF) can be used to produce range images at any distance, but suffers from errors due to multipath and other factors. Active triangulation/structured illumination on its own is able to produce range images that do not suffer from multipath and are thus more suitable for applications such as object capture (which requires high accuracy). However, the active triangulation/structured illumination sensor can suffer performance problems if either the pattern or optics change over time (e.g., due to physical shock).